Switching mechanism



' June 6, 1944. FfH. HIBBARD SWITCHING MECHANISM Filed May 1e, 194s ssheets-sheet 1 /NVE/VTOR f.' hf H/BBARD By June 6, 1944. F; H. HIBBARDSWITCHING MECHANISM s sheets-sheet 2 Filed May 18, 1943 Patented June 6,1944 UNITED STATES PATENT OFFICE SWITCHING MECHANISM York ApplicationMay 18, 1943, Serial No. 487,433

'7 Claims.

This invention relates to switching mechanisms and particularly to suchmechanisms as are employed in automatic telephone systems for theestablishing of connections.

An object is to simplify and reduce the cost of such mechanisms and tomake them more readily controllable by outside electrical circuits.

Heretofore, crossbar switches have been used in which bars and rows ofcontacts are coordinately arranged so that the operation of a select barin one coordinate direction by a corresponding select magnet followed bythe operation of a hold bar in the other coordinate direction by acorresponding hold magnet causes connections to be closed betweencontacts at the intersecting points of said two bars. In certainarrangements of this type of switch, each select bar is arranged toserve two rows of contacts by being rotated in one direction or theother by a corresponding select magnet.

The present invention relates to improvements in a switch of this lattertype whereby in place of the individual magnets for a plurality ofselect bars, the operations of these bars are controlled by two magnetsonly in response to dial pulses incoming to said switch. That is, aplurality of such select bars are controlled in their selectivemovements by two common magnets and a common associated controlmechanism. If a switch is considered in which, for example, five selectbars are located horizontally and ten hold bars vertically, the presentinvention would provide a vertical shaft at one end of the select barshaving ten projections thereon arranged in a helical formation, whileeach select bar is provided with a crosspiece or oppositely extendingarms with the outer end of each arm in a position in line with acorresponding projection on the vertical shaft. This vertical shaft isrotatable in steps by a pawl and ratchet mechanism controlled by asingle magnet responsive to dial pulses incoming to the switch. Thismagnet, pawl and ratchet mechanism and shaft are mounted on a framewhich may be shifted by another single magnet to swing away from thearms on the select bars and to be returned to normal by a spring. Thefunctioning of this mechanism is such that the frame containing theshaft, the pawl and ratchet mechanism and the magnet operating it isshifted in a position where the projections on the shaft will notinterfere with the arms on the select bars. The shaft is then rotated insteps until a certain projection on the shaft is placed opposite aparticular arm. The frame is then released tion will engage thecorresponding arm on a. select bar to rotate it in the proper direction.

Another feature is an arrangement whereby the shaft remains in rotatedposition after each operation of a select bar and is restored to normalwhen a succeeding selection is initiated, that is on a succeedingoperation of the magnet for shifting the frame, mechanism is providedwhich releases the shaft to its normal position in readiness for asucceeding rotation thereof by the pawl and ratchet mechanism and itsmagnet to select a select bar for rotation on the subsequent release ofthe frame to normal.

The invention has been illustrated in the accompanying drawings inwhich:

Fig. 1 shows a front view of a typical crossbar switch in which theapplicants invention has been incorporated;

Figs. 2, 3 and 4 show various control positions of certain of themechanisms of applicants invention;

Fig, 5 is a fragmentary perspective view of a portion of a horizontaland a vertical bar and the contact sets at the cross-point of thesebars;

Fig. 6 is a detailed view of the operating shaft and the horizontal barsof the switch looking at one end of these bars; and

Fig. 7 is a top view of the switch particularly relating to off-normalcontacts of the applicants invention as controlled by the operatingshaft.

Referring now to the drawings, the switch consists of an upper framemember I, a lower frame member 2, a left-hand member 3 and a righthandmember 4 with intermediate left-hand supporting member 5 and right-handsupporting member 6 connected between the members I and 2. Between thesemembers 5 and 6 are pivoted five horizontal bars marked generally withthe numeral I0 and between the upper and lower members I and 2 aremounted what are generally referred to as vertical units, eachcomprising contacts and a vertical bar such as bar II with itsassociated magnet I2 for rotating it. This vertical bar is mounted on aframe I3 attached to the upper and lower frame members I and 2 withscrews as shown. On this frame member I3 are also mounted individualcontact springs. At each cross-point of a vertical and a horizontal barthere are located an upper group of contacts I5 and a lower group ofcontacts I6 of two horizontal rows of contact springs and associatedwith these sets of horizontal contact springs are vertical contactstrips I1 with which the horizontal contact springs may establishconnections to normal condition so that the selected projecrespectivelyOn the Operation of the mechanism as will be described more fully inconnection with Fig. 5. It is sufficient to say at this time that thehorizontal bars le may be rotated in a clockwise direction looking atFig. 1 from the left to cause the actuation of the upper contacts l5 androtated in a counter-clockwise direction to cause the actuation of thelower contacts I6 to connect with the strips Il on the operation oftheassociated vertical bar Il by a magnet l2.

The applicants invention has been applied to this mechanism to eliminatethe usual operating magnets for rotating the horizontal bars in thesetwo directions and consists of the following parts. Between the membersl and 2 are secured by brackets, such as 2) on frame member l and 2| onframe member 2, a vertical frame member 24 by means of a leaf hinge 25secured to members 2| and 24, and a leaf hinge 25 secured to members 25and Z4 so that the member 24 will be hinged at each end for rotationunder control of an armature extension on the member 24, marked 27,controlled by a magnet 23 mounted on a yoke piece 29 secured by abracket 35 to the lower frame member 2. The member 24 is held in normalposition by means of a spring 32 secured to a projection 33 on member 24and at the opposite end to a projection 34 on the frame member 5. Thenormal position occupied by the member 24 is determined by an angularextension at the top marked 36 shown particularly in 7, which engages astop member 58 secured with the bracket 20 on the frame member l.Between this angular extension 36 at the top of member 24 and a bracket45, secured to the bottom of member 24 by means of an `angular extension42 and screws 43, is journaled a shaft 44. Surrounding this shaft is asleeve 45 having helically arranged extensions such as 46 and 4l, eachof which is located opposite a corresponding arm such as 48 and 49, forexample, extending from the bracket 50 connected to the lower horizontalbar l5. That is, each horizontalbar lil is provided with such a bracket55 with a lower arm 48 and an upper arm 49. Each one of these arms onthe different bars is as stated opposite a corresponding projection onthe sleeve 45, but normally out of engagement with these projectionswhen the shaft is in normal position. The shaft also has an upperprojection 5i which normally engages a spring stop 52 connected to theframe member l. At the bottom of sleeve 45 and between this sleeve andthe bracket 45 is located and secured a normal stop member 53 tomaintain the shaft in normal position and two ratchet wheels 54 and 55in the order named with the member 53 nearest bracket 45. Ratchet wheel55 is used for rotating the shaft in operative positions in steps andratchet wheel l54 is used as a stop ratchet. The shaft 44, sleeve 45,ratchet wheel and the stop 53 `are returned to normal by means of aspiral spring secured at the lower end to the shaft 44 and at the upperend to bracket 45. The stop member 53 engages normally the hooked end 5lof the spring member 58 which end in turn engages the downwardlyextending projection 55 on a bracket 60 secured to bracket 4B by meansof screws 6l. This bracket 65 has an upwardly extending projection 63which extends through an opening 64 in bracket 45 and to which isconnected a holding pawl 65 engaging the ratchet wheel 55. This holdingpawl 65 prevents the ratchet wheels from rotatingin a counter-clockwisedirection after having been advanced in a clockwise direction as will bedescribed hereinafter. This bracket 45 is provided with in a clockwisedirection under circumstances as will be described hereinafter.

On the frame member 5 is mounted an operating magnet 68 having anarmature 69 pivoted at l and held in normal position by spring Ilsecured at one end to the projection 'l2 of the armature 69 and at theother end secured to the frame member 5 in any suitable manner notshown. The back stop member 13 secured to the frame member 5 engages theprojection 'i2 to hold the armature in its normal position. The armatureB9 is provided with an extension arm i4 at the end of which is secured astepping pawl l5 engaging the ratchet wheel 55. At the end of extension'i4 is also a downwardly bent membel1 'l1 which engages the pawl `57when the armature 59 is attracted by the magnet 58 to pull this pawlaway from the ratchet wheel 54. On the pivot 79 secured to bracket '60is mounted la lever 80, one end of which, marked l8|, is bent down toengage the pawls `55 and 75 to remove them from engagement with theratchet wheel 55 when this lever is rotated in a clockwise direction.The opposite end of this lever is also bent downwardly as shown at 82 tobe engaged by a tooth 83 on the spring 58, the purpose of which will bedescribed hereinafter. The spring 58 is flexibly con-y nected by meansof a leaf spring 85 to a bracket 86 secured to frame 5. On the bracket25 is also secured a pile of olf-normal springs which are controlledthrough the medium of stud 92 engaged by the extension 35 when themember 24 is rotated.

A description will now be made of the operation of this mechanism toselect and establish connections at a cross-point between a horizontalbar and a vertical bar. Fig. 2 illustrates the normal position of thearmatures 2l and 69 with the shaft 44 and all the other parts in normalposition. The rst thing that occurs is that the magnet 23 is energizedto attract the armature 21 and rotate the member 24 and bracket 40 toshift the position of shaft 44 and its associated parts away from thearms on the brackets 50 so that the shaft 44 may be free to rotate insteps to select a particular horizontal bar for rotation in onedirection or the other. The magnet 68 is then operated in steps toalternately attract and release armature 69 and thus cause the pawl 15to engage the ratchet wheel 55 and rotate it each time the armature andpawl are returned to nor mal, under tension of the spring 1l. When thearmature 69 is attracted, extension Tl engages pawl 51 and removes itfrom the ratchet wheel 54 and this pawl remains out of engagement withthe teeth of wheel 54 until the stepping pawl l5 has started toadvancethe wheels at which time it is released beyond the tooth it formerlyengaged and when the step is completed, the pawl 6l will engage the nexttooth to prevent further forward movement of the ratchet wheels at thistime. Pawl 65 will also engage the next tooth in wheel 55 to prevent theratchet wheels from restoring under tension of the return spring 56.Thus for each operation and release of armature 69, the ratchet wheels54 and 55 and the sleeve 45 are rotated one step to bring a succeedingextension such as 46 in front of an associated arm such as 48 on abracket 56. That is, the rst projection 45 will be placed opposite thearm 48 on the first rotary step of sleeve 45 and the next projection 41will be placed opposite the arm 49 on the second step and so on, sc thatwhen the armature 59 ceases to operate only one of the projections onthe sleeve 45 will be opposite a corresponding arm on a correspondinghorizontal bar. It should now be observed that as the shaft 44 isrotated, the step 53 will be rotated with the shaft and thus cause therelease of the spring 58 permitting this spring to move towards theleft, but at this time the pawl 83 on this spring 53 will not hook underthe extension 82 on lever 89 due .to the operated position of armature21, but will merely engage the inner right-hand surface of extension 82at this time and as shown in dotted lines in Fig. 4.

The next step will be to have the armature 21 released by the magnet 28,thus shifting the shaft 44 and all the associated parts towards thehorizontal bars and in so doing one or the projections on the sleeve 45will engage the associated arm on the associated horizontal bar androtate it in a corresponding direction. For example, if only a singlestep has been taken, the first or the lower projection 46 will engagethe arm 48 and rotate the lower horizontal bar in a counter-clockwisedirection. On the other hand, if two steps had been taken, theprojection 41 would engage the arm 49 of the same horizontal bar torotate it in a clockwise direction.

` If, for example, the upper bar Ii) had been rotated in a clockwisedirection, it would have shifted its fingers 91, referring especially toFig. 5, so that this finger will be in position opposite a slot 98 in anoperating card 99 for the horizontal springs I5. Then when a verticalbar, for example, bar II, is rotated by its magnet I2, the extensionIIlI engages the finger 91 and presses it against the card 99 which nowshifts the springs I to engage with the contact strips I1 in the usualmanner in switches of this type. If this horizontal bar had beenoperated in the opposite direction, finger 91 would have engaged a slotin card |92 and on the Operation of the vertical bar I I the projectionIIlI would have caused the finger to shift the card |92 to cause thesprings I6 to engage with the contact strips I1. Thus the operation ofany horizontal bar and any vertical bar will establish electricalconnections between contacts at the intersecting point of these twobars. It will therefore be seen that the operation of magnet 28 followedby the operation of the magnet 68 in steps and the release of magnet 28causes the selection and rotation of a horizontal bar in the properdirection to prepare for the establishing of a connection in theparticular horizontal row of contact springs and thus this mechanismwill replace the usual ten operating magnets for controlling the fivebars in wellknown crossbar structures.

As both magnets 28 and 68 are released after a, selection, thehorizontal bar selected will remain in the actuated position untilanother connection at another cross-point is desired. When this is aboutto take place, the operations will be the same as before except that inthis case the shaft 44 and its associated parts will have to be restoredto normal before the selection for a new connection is begun. It shouldbe observed, therefore, that when armature 21 has released and the lever80 shifted to normal, the projection 82 releases the panel 83 and spring58 which then caused the panel 83 to be hooked under the projection 82.Thus when magnet 28 again attracts the armature 21, the pawl 83 willrotate lever 80 in a clockwise direction and thereby cause the extension8l to engage the pawls 65 and 15 and remove them from engagement withteeth on ratchet wheel 55 and thus permit the shaft 45 t0 rotate back tonormal under tension of the spring 5B. In Fig. 3, the shaft 44 andassociated parts have been shown in a position where the lever has thusreleased the shaft 44 and where the shaft has rotated back towardsnormal so that the normal stop 53 is about to engage the spring 58, andpull this spring towards the right until the stop and spring engage theprojection 59 on the vbracket I 5. When spring 58 is being thusrestored,

it will withdraw the pawl 83 from the extension 82 on the lever 80 andthereby permit the lever 80 to return to normal under tension of thepawls 65 and 15 which again engage teeth in ratchet wheel 55. With thearmature 21 actuated and the shaft 45 shifted away from the arms on thehorizontal bars, the mechanism is again positioned for control by magnet68 to select another horizontal bar for rotation as hereinbeforedescribed.

What is claimed is:

l. In a crossbar switch, select bars and hold bars coordinatelyarranged, contacts at each cross-point of said bars, a select barselecting and operating means including a select rod having helicallyarranged projections thereon, a ratchet mechanism for said rod, a magnetfor actuating said ratchet mechanism, a mounting for said rod andratchet mechanism, an operating magnet for controlling said mounting tomove said select rod so that the selected projection engages thecorresponding select bar to move it and means responsive to the movementof said select bar followed by the movement of a hold bar for actuatingthe contacts at the corresponding cross-point.

2. In a crossbar switch, select bars and hold bars coordinatelyarranged, contacts at each cross-point of said bars, selecting andoperating means for said select bars including a rod having helicallyarranged projections, one for each select bar, a pawl, a ratchetmechanism for said rod, a magnet for actuating the pawl to rotate therod in steps and a mounting for said rod and ratchet mechanism, anoperating magnet for moving said mounting by an operative stroke so thatduring the rotation of said rod in steps the projections will notinterfere with said select bars and for releasing said mounting on arelease stroke so that the selected projection on said rod will actuatethe corresponding select bar, means responsive to a subsequent operativestroke of said operating magnet for actuating said pawl and ratchetmechanism to release said rod from the position to which it has beenrotated and permit its return to normal position and means responsive tothe actuation of said select bar followed by the actuation of a hold barfor operating the contacts at the cross-points of said bars.

3. In a crossbar switch, select bars and hold bars coordinatelyarranged, contacts at each cross-point of said bars, a rod havinghelically arranged projections, one for each select bar, a magnet, apawl and ratchet mechanism associated with said rod for control by saidmagnet to rotate the rod in steps, means for maintaining said rod in aposition during the rotation of said rod in steps so that theprojections thereon do not interfere with the respective select rods andfor actuating a select bar by a projection on said rod depending on theextent of the rotary movement and means operative on the actuation of aselect rod followed by the actuation. of a hold bar for establishing aconnection at the crosspoint of said bars between the contacts thereat.

4. In a crcssbar switch, select bars and hold bars arrangedcoordinately,V contacts at each cross-point of said bars, a select rodhaving helically arranged projections, one for each select bar, meansfor rotating said select rod to place any projection opposite acorresponding select bar, means for preventing the projections fromtouching the select bars during the rotary movement of Said select rodand for shifting said select rod after it has been rotated to cause theprojection placed opposite a select bar to rotate said select bar andmeans responsive to the rotation of said select bar and the actuation ofa hold bar for operating the corresponding contacts at the cross-pointoi said bars.

5. In a crossbar switch, select bars and hold bars arrangedcoordinately, contacts at each cross-point of said bars, a select rodhaving helically arranged projections, two projections for each selectbar, means for rotating said select rod in steps to place one or theother of any pair of projections in position to act on a correspondingselect bar, means for preventing the projections irom touching theselect bars during the rotary movement of said select rod and forcausing the projection placed in position to act to rotate theassociated bar in a certain direction, and means responsive to therotation of said select bar in said certain direction followed by theactuation of a hold bar for operating a corresponding set of contacts atthe cross-point of said bars.

6. In a crossbar switch, horizontal and vertical bars coordinatelyarranged, contacts at each cross-point of said bars, a select rod havinghelically arranged projections, means for 'rotating said rod in steps,means operative to move said select rod laterally to cause a particularprojection, depending on the extent of the rotary movement of saidselect rod to actuate a corresponding horizontal bar, means responsiveto the actuation of said horizontal bar followed by the actuation of avertical bar for actuating the contacts at the cross-points of saidbars,

'7. In a crossbar switch, horizontal and vertical bars coordinatelyarranged, contacts at each cross-point of said bars, a select rod havinghelically arranged projections, means for rotating said rod in steps,means operative to movev FRANK H. HIBBARD.

